Electrical switch



NV 14, 1950 c. A. wooDwARD 2,530,364

ELECTRICAL SWITCH Filed Jan-` 14, 1949 lllllllllllll '11114rlllllllllllllll 'a I6 I8 lo ATTOR NEY.

Patented Nov. 14, 17950 ELECTRICAL SWITCH Clement A. Woodward,Wellesley, Mass., assignor to United-Carr Fastener Corporation,Cambridge, Mass., a corporation of Massachusetts Application January 14,1949, Serial No. 70,890

2 Claims.

This invention relates generally to electrical switches, and hasparticular reference to a switch adapted to be operated by a closuremember such as an automobile door.

Plunger operated electrical switches are frequently provided in doorframe moldings in automobiles to turn on and oif an internal light whenthe door is opened` and closed. The switch is usually mounted behind themolding and is provided with a spring mounted operating plunger, whichis extended when the door is open and forced inwardly when the door isclosed.

Although switches used for such installations are generally satisfactoryin operation when rst installed, it has been found that after prolongeduse, the plunger operating spring becomes too weak to effect goodelectrical contact between the switch contact elements. Consequently,only a slight force on the plunger is necessary to break the electricalContact in the switch and in many cases, even slight vibrations impartedto the switch causes undesirable flickering of the light.

-The object of the invention is to provide a plunger operated electricalswitch, in which appreciable movement of the plunger is necessary toseparate electrical contacts in the switch.

A. further object of the invention is to provide an electrical switchhaving cooperating contact members which are forced together by dualspring means, in which the dual spring means are arranged to permitmovement of one Contact member a predetermined distance beforeelectrical Contact between the members is broken.

A still further object of the invention is to provide an electricalswitch having a contact member mounted by spring means on a basedisposed for movement toward and away from another contact member, inwhich the spring means allows the contact members to maintain electricalcontact during movement of the base a predetermined distance away fromthe other `contact member.

A still further object of the invention is to provide an electricalswitch having contact members disposed to be forced together by anoperating spring and an auxiliary spring, whereby extension of theoperating spring to force the members into contact causes compression ofthe auxiliary spring.

Other objects of the invention will, in part, be obvious, and will, inpart, appear hereinafter.

For fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description, taken inconjunction with the accompanying drawing, in`

which:

Fig. 1 is an exploded view of the component parts of the device;

Fig. 2 is a view in elevation, partly in section, of the assembleddevice, in which the switch is in the on position;

Fig. 3 is a View similar to Fig. 2 in which the switch operating plungerhas been moved inwardly a predetermined distance, but not sufficientlyfar to break the electrical contact;

Fig. 4 is a view similar to Fig. 2 in which the Switch is in the oifposition;

Fig. 5 is a view in section taken on line 5-5 of Fig. 2;

Fig. 6 is a view in section taken online 6-6 of Fig. 2. y

Referring to the drawing there is illustrated a push button switchassembly I0, which is adapted to snap into engagement with a doormolding I2, and is disposed for operation by an associatedclosurefmember I4. The switch I0 comprises a pair of contact members I6ymounted on a base I8 which is movable within a housing 20,r and ashorting ring 22 mounted opposite the contact.

members on a xed base 24. The xed base 2.4 is provided with an opening26 for a purpose which will appear hereinafter. The movable base I8 isslidable in the housing 20 toward and away from the fixed base 24 tomake and break an electrical circuit between the members I6 and theshorting ring 22.

The Contact members I6 are so mounted on the movable base I8 as to allowmovement of the members a predetermined distance toward and away fromthe base, and are biased outwardly from the base by Contact springs 28mounted behind the Contact members in recesses 30. To provide forelectrical connections to the contact members, openings 32 are providedin the base I8, through which lead wires 34 may be disposed.

An operating plunger 36 is mounted on the base I3 to extend through theopening 26 in the fixed base, and protrudes from the housing 28 when theswitch is in the on position. An insulating stop ring 38 is provided onthe plunger 36 to engage the contact members I6 and limit the distancethey may be extended by the contact springs 28.

A switch operating spring 4@ is disposed in the housing behind themovable base I 8, to bias the base and the contacts toward the shortingring 22, and to extend the plunger from the housing. The operatingspring 40 should be appreciably stronger than the combined strength ofthe contact springs, for a purpose which will appear hereinafter.

'Ihe operation of the switch is best illustrated by Figs. 2 4. As shownin Fig. 2, the switch is in the on position when the plunger is extendedby the biasing force of the operating spring 40 bearing against themovable base I8, thereby forcing the contacts I6 against the shortingring 22, to complete an electrical circuit between the contacts. Thebiasing force of the spring 40 also compresses the contact springs 28 byforcing the contacts I inwardly toward the base I8.

As illustrated in Fig. 3, when the closure member I4 bears against theplunger 36, the plunger and base I 8 are forced inwardly, compressingthe operating spring 40. Movement of the base I8 away from the base 24allows the contact springs 28 to expand, forcing the contact members I6away from the base I8 to maintain them in contact with the shorting ring22. As illustrated in Fig. 4, when the closure member I4 forces theplunger 3B and base I 8 further inwardly, the contact members I6 engagethe stop ring 38, and further movement of the plunger and base inwardlymoves the Contact members away from the shorting ring 22 to break theelectric circuit therebetween.

It will be readily apparent that numerous modications may be made in thedevice. For instance, in some cases it may be desirable to have only onecontact member mounted on the movable base, in which case the shortingring may be replaced by a single Contact member which may be grounded tocomplete an electrical circuit. If it is more convenient to mount thecontact members solidly on the movable base, auxiliary springs may bemounted between the shorting ring and the fixed base, or between thefixed base and the housing to achieve the desired resiliency between theContact members.

Since certain other obvious changes may be made in the device withoutdeparting from the scope of the invention, it is intended that allmatter contained herein be interpreted in an illustrative and not in alimiting sense,

I claim:

1. An 4electrical switch comprising a substantially tubular casinghaving inturned flanges at one end dening an opening, an insulating endmember secured in the other end of said casing having an apertureextending therethrough into the casing, and a shorting contact membersurrounding the aperture on the face disposed within the casing, acontact-carrying member of insulating material disposed within saidcasing provided with an operating plunger extending through the apertureof said insulating end member, said contact-carrying member havingcontact-receiving cavities on a face opposite said end member, andcontact-retaining means on said plunger overlying said cavities, contactmembers loosely disposed in said cavities, connecting wires extendingfrom said contacts through said contact-carrying member and the openingdefined by said inturned flange, spring means disposed in said contactcavities for urging said contacts toward said contact-carrying means,and other spring means disposed in said casing between said ange andsaid contact-carrying member for urging said contact-carrying membertoward said other end, said plunger through said aperture, and, saidcontacts into contact with said snorting Contact member.

2. An electrical switch in accordance with claim 1 wherein thecontact-retaining means on the plunger comprises an insulating ringsecured to said plunger in spaced relation to said contact-carryingmember.

CLEMENT A. WOODWARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 731,375 Liggett June 16, 19031,071,169 Mertz Aug. 26, 1913 2,436,898 Rickmeyer Mar. 2, 1948Certificate of Correction Patent No. 2,530,364 November 14, 1950 CLEMENTA. WOODWARD It is hereby certified that error appears in the printedspeccaton of the above numbered patent requiring eorrectlon as follows:

Column 4, line 22, for the hyphenated Word contact-carrying readcontact-@Mining and that the said Letters Patent should be read ascorrected above, so that the same may conform to the record of the casein the Patent Office. Signed and sealed this 9th day of January, A.. D.1951.

[SEAL] THOMAS F. MURPHY,

Assistant @ammissioner of Patents.

Certificate of Correction Patent No. 2,530,364.- November 14, 1950CLEMENT A. WOODWARD It is hereby certed that error appears in theprinted speceaton of the above numbered patent requiring correction asfollows:

Column 4, line 22, for the hyphenated Word contact-carrying readcontact-retaining and that the said Letters Patent should be read ascorrected above, so that the same may conform to the record of the casein the Patent Oce. Signed and sealed this 9th day of January, A. D.1951.

[SEAL] THOMAS F. MURPHY,

Assistant ommz'ssz'oner of Patents.

